Most utilities in California currently offer net metering, which effectively allows you to bank your energy until you need it, virtually eliminating your electric bill.
Net metering lasts for a whole year, so you can build credit in the summer for those darker winter days. It measures the difference between the electricity you buy from the utility and the electricity you generate with your solar panel system.
When you are making more electricity than you are using, such as on summer days, your extra electricity automatically gets metered back (sold) to the utility grid. You receive credit for this power at the same rate that the utility sells it to you.
Net metering allows you to use the electric utility grid like a bank account. You can put electricity into it that you don’t use immediately and you can withdraw the same amount later (such as at night) at no net cost to you.